EP0786599B1 - Fluid pressure operating means with a cylinder and a plunger piston - Google Patents

Abstract

The plunger piston (3) can be withdrawn from the passage bore (13) in the abutment and from the sealing ring (8), without dismantling the abutment. The abutment is formed as a sliding body, and forms a diametrical dove-tail connection with the end of the cylinder (1). When in inserted position, the abutment is locked by the piston relative to the cylinder. The dove-tail connection has two diametrically opposite slide rails, which are inserted into complementary cross grooves (9, 10) in the cylinder. The sliding body has a ring groove (16) with stripper ring.

Description

The invention relates to a pressure medium drive according to the preamble of the claim 1.

Such pressure medium drives, which are usually designed as hydraulic drives are in large quantities, for example for industrial trucks such as forklifts etc. needed. There is an abutment at the end of the cylinder, which at least partially also serves as a guide for the plunger. This Abutment also absorbs the axial forces of the sealing ring.

From DE 36 35 020 A1 it is in a generic pressure medium drive known, a rack that is connected to a piston by a Abutment, namely by a work space end piece with an inner and an outer seal, and the abutment through a radial Prestressed circlip consisting of a round wire in the cylinder to be determined. Because the piston has a larger diameter than that Rack, the rack cannot come out of the abutment be pulled out. Rather, the circlip must be by means of a Tool in the narrow annular gap between the rack and the Cylinder used and in the event of a repair also from the Annular gap to be expanded. Manufacturing and repair are therefore complex, and the round wire provides for extremely high working pressures numerous use cases represent a weak point.

From US 33 91 612 it is known to have a larger cross section Piston seal of the piston of a hydraulic motor through a Connect the dovetail connection to the piston. Around To be able to connect and disconnect is in the Cylinder wall provided a radial opening through a cover is closed with screws that can only be removed by a tool. The piston itself must be in the cylinder until the piston seal is removed remain; pulling out of the bore of an abutment nothing revealed. Regarding one at the end of the cylinder Breech wall, which can be referred to as an abutment stated that this also through an identical radial opening in the Cylinder wall is inserted and removed. A seal change and the associated design is complex, especially since none Extruded profiles can be used for the manufacture of the cylinder. The radial assembly shafts for the seals also provide marked weaknesses on their lids compared to high ones Press.

All known types of attachment are either indefinite or expensive, taking into account that such Pressure fluid drives are required in large numbers.

The invention is therefore based on the object of a pressure medium drive Specify that simple to manufacture and using fewer parts is in which the abutment has a precise fit and the sealing ring is easy to replace.

The solution to the problem is the one specified at the beginning Pressure medium drive according to the invention by the features in the characteristic of Claim 1.

It is advantageous if the piston is in one in the cylinder chamber inserted guide ring is guided and if the sealing ring between the Guide ring and the sliding body is arranged, especially if the Guide ring made of a slidable plastic and in one Stepped bore of the cylinder chamber is arranged.

In the subject of the invention, only a small number of parts are required, from which the abutment has a precise fit in the open end of the cylinder occupies at least part of the piston guidance, a precise Support for the sealing ring guaranteed and its replacement on enables simple way. Special Sleeves and threaded holes at the cylinder end are not required, likewise no additional sealing plates and none Sealing rings.

The plunger itself serves as a surprisingly simple way Locking device for the sliding body; other fasteners are not needed. As long as the plunger in the cylinder piston is inserted, the sliding body can not from the transverse grooves in the Cylinders are pushed out. Is the plunger out of the cylinder pulled out, so the sliding body can be perpendicular to Slide the cylinder longitudinal axis out of the transverse grooves so that then also the sealing ring without special tools pulled out its stepped bore and through a new one Sealing ring can be replaced. The sliding body is also arbitrary often reusable.

It is special in the course of an embodiment of the invention advantageous if the sliding body in the axial direction has a rectangular outline (including a square outline too understand) and if the sliding strips on two opposite Sides of the rectangle are arranged.

It is again in the course of a further embodiment of the invention particularly advantageous if the sliding body within the Through hole for the plunger is provided with an annular groove in a wiper ring is inserted.

This wiper ring can also be easily levered out of the ring groove and replace with a new one. As long as the wiper ring is reusable, it remains in the sliding body and can with this after replacing the sealing ring in the transverse grooves are inserted, whereupon the renewed locking by the Plunger takes place.

Two embodiments of the subject matter of the invention explained in more detail below with reference to FIGS. 1 to 8.

Figur 1

. einen teilweisen Axialschnitt durch einen vollständigen Druckmittelantrieb,

Figur 2

eine stirnseitige Ansicht des Gegenstandes nach Figur 1 in Richtung des Pfeils II,

Figur 3

das linke Ende von Figur 1 in vergrößertem Maßstab,

Figur 4

einen Axialschnitt durch den Schiebekörper entlang der Linie IV-IV in Figur 5,

Figur 5

eine Ansicht des Schiebekörpers nach Figur 4, in Richtung des Pfeils V,

Figur 6

einen Axialschnitt durch einen doppelseitigen Druckmittelantrieb gemäß Figur 1, wie er beispielsweise für sogenannte Seitenschiebereinrichtungen für Gabeln von Gabelstaplern verwendet werden kann,

Figur 7

eine Explosionsdarstellung des Gegenstandes nach den Figuren 1 bis 5 im Zusammenhang mit einem Doppelzylinder nach Figur 6 und

Figur 8

eine Variante des Gegenstandes nach Figur 1 in Explosionsdarstellung.

Show it:

Figure 1

, a partial axial section through a complete pressure medium drive,

Figure 2

2 shows an end view of the object according to FIG. 1 in the direction of arrow II,

Figure 3

the left end of Figure 1 on an enlarged scale,

Figure 4

5 shows an axial section through the sliding body along the line IV-IV in FIG. 5,

Figure 5

3 shows a view of the sliding body according to FIG. 4, in the direction of arrow V,

Figure 6

2 shows an axial section through a double-sided pressure medium drive according to FIG. 1, as can be used, for example, for so-called side shift devices for forks of forklift trucks,

Figure 7

an exploded view of the object according to Figures 1 to 5 in connection with a double cylinder according to Figure 6 and

Figure 8

a variant of the object of Figure 1 in an exploded view.

In Figure 1, a cylinder 1 is shown with a cylinder chamber 2 in which a plunger 3 is arranged, which is also referred to as a plunger. By a diameter difference between the cylinder chamber 2 and the plunger 3, an annular gap 4 is formed, in one Connection bore 5 opens for a hydraulic line, not shown.

The end of the cylinder chamber 2 is slightly enlarged in diameter, and in this extension a guide ring 6 is used, which consists of a good sliding plastic, such as polyamide. On this extension is followed by a stepped bore 7 Sealing ring 8 is used, which in the manner shown as a groove or Lip ring is formed.

This stepped bore 7 is in turn connected to one another parallel transverse grooves 9 and 10, which have a prismatic cross section and run across the entire cylinder 1, i.e. on both ends are open. Are towards the end of cylinder 1 these transverse grooves 9 and 10 each delimited by a claw 11, which is parallel runs to the respective transverse groove 9 or 10 and with each one Sliding seat forms.

In the transverse grooves 9 and 10 is a sliding body in the diametrical direction 12 inserted, which has a through hole 13 for the plunger 3 having. As can be seen from Figure 1, the sliding body 12 forms Abutment for the sealing ring 8, which in the direction of the Cylinder opening is under the pressure of the hydraulic fluid, which is up to Is 300 bar, but this value is not a critical upper limit represents.

As can be seen from Figure 2, the sliding body 12 in both Directions according to the double arrow 14 perpendicular to the axis A. be pushed out. In the axial direction, the sliding body 12 however reliably by the transverse grooves 9 and 10 or by the claws 11 held.

As can also be seen from FIG. 3, the sliding body 12 has one Contact surface 15 for the sealing ring 8 and on the opposite Side within the through hole 13 an annular groove 16 (Figure 4) for the inclusion of a scraper ring 17. This scraper ring can vary depending on Findings can be reused; he does not need a metal frame because the Sliding body 12 takes over this function. How to look special Figure 3 shows the scraper ring 17 in all directions by the Walls of the annular groove 16 and held by the plunger 3; he can however, after pulling out the plunger 3 without further ado be pried out or rolled out.

As can be seen from FIGS. 4 and 5, the sliding body 12 has axial viewing direction according to arrow V a rectangular outline, wherein on two opposite sides of the rectangle R two to each other parallel sliding strips 18 and 19 are arranged, which also one have a prismatic cross section and to the transverse grooves 8 and 9 are arranged and designed complementary. This results in between the sliding body 12 and the cylinder 1 a kind Dovetail connection that ensures an extremely precise fit of the Slider body 12 guaranteed.

1. Tauchkolben herausziehen,

2. Schiebekörper 12 seitlich aus den Quernuten 9 und 10 herausschieben,

3. Dichtungsring 8 und ggf. auch Abstreifring 17 auswechseln,

4. Schiebekörper 12 von der Seite her wieder einschieben und

5. Tauchkolben in axialer Richtung einschieben.

FIG. 6 also shows a double cylinder 20 with two cylinder chambers 2a and 2b, which are separated from one another by a partition wall 21. The two cylinder chambers 2a and 2b can be acted upon independently of one another by two connection bores 5a and 5b. Since such a plunger requires an external stop to limit the stroke, such pressure medium drives are preferred, but not exclusively, used in so-called side shift devices with a side shift frame 22, the upper part of which, like the plungers 3a and 3b, are shown in dashed lines in FIG. 6. By alternately acting on the two plungers 3a and 3b, the sideshift frame 22 can be shifted by the dimension "s" on both sides. For example, when the plunger 3a is pushed out further, the plunger 3b is pushed back by an identical amount. In any case, however, the side shift frame 22, which forms the necessary stops, prevents the plungers 3a and / or 3b from escaping. After removing the sideshift frame 2, the sealing rings 8 and possibly also the wiper rings 17 can be replaced as follows:

1. Pull out the plunger,

2. Push the sliding body 12 sideways out of the transverse grooves 9 and 10,

3. Replace sealing ring 8 and, if necessary, wiper ring 17,

4. Push the sliding body 12 in again from the side and

5. Insert the plunger in the axial direction.

The idea of the invention is both for cylinders with rectangular or square outer contour applicable (Figure 7), as well as with cylinders, which, for example, have an outer cylindrical surface (FIG. 8). In the Figures 7 and 8 are the same parts with the same reference numerals Mistake. in Figure 8, the cylinder 1 according to Figure 1 by a Cylinder 23 replaced with a cylindrical outer surface, the one has the appropriate wall thickness to a sufficient length of the To enable transverse grooves 9 and 10 and the sliding strips 18 and 19.

Claims (6)

1. Fluid pressure operating means with a cylinder (1, 23) with a cylinder chamber (2, 2a, 2b), a radially guided piston (3, 3a, 3b), a sealing ring (8) and an exchangeable abutment (12) with a throughbore (13) for the piston (3, 3a, 3b) and with a seating surface (15) for the sealing ring (8),
   characterised in that

   a) the piston (3, 3a, 3b) is designed as a plunger piston which is extractable from the throughbore (13) and the sealing ring (8) without disassembly of the abutment (12);

   b) the abutment (12) is designed as a sliding body (12) and insertible into the end of the cylinder (1, 23), being exchangeable in the radial direction by means of diametrically opposite sliding webs (18, 29) and complementary transverse grooves (9, 10), though being secured in the axial direction, and the sliding webs (18, 19) and the transverse grooves (9, 10) have prismatic cross-sections and form a kind of dovetail connection; and

   c) the inserted abutment (12) is arrested by the piston (3, 3a, 3b) in its sliding direction relative to the cylinder (1, 23).
2. Fluid pressure operating means according to Claim 1, characterised in that the sliding body (12) has a rectangular outline, as seen in the axial direction, and the sliding webs (18, 19) are arranged on two opposite sides of the rectangle (R).
3. Fluid pressure operating means according to Claim 1, characterised in that the sliding body (12) is inside the throughbore (13) provided with an annular groove (16) into which is inserted a stripping ring.
4. Fluid pressure operating means according to Claim 1, characterised in that the piston (3, 3a, 3b) is guided in a guide ring (6) which is inserted into the cylinder chamber (2, 2a, 2b), and the sealing ring (8) is arranged between the guide ring (6) and the sliding body (12).
5. Fluid pressure operating means according to Claim 4, characterised in that the guide ring (6) is made of a slidable plastic material.
6. Fluid pressure operating means according to Claim 4, characterised in that the sealing ring (8) is arranged in a stepped bore (7) of the cylinder chamber (2, 2a, 2b).

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